Publications

Shell Research B.V. has developed additives- - that can effectively solve problems caused by wax. They are widely used in areas ranging from the oil well to pipeline transport, and from refinery operation to products. Thus, their remedial activity has been proven in paraffin deposition in oil wells low temperature fluidity of waxy crude oils in pipelines, and depression of pour points in waxy residual fuel oils.SHELLSWIM additives modify the crystal structure of wax crystallizing from a waxy crude oil or waxy residual fuel oil upon cooling. Their effect is demonstrated by the reduction of the pour point of, for instance, Seria Light crude oil, where the addition of 0.01 %w of SHELLSWIM - 11T reduced the pour point by 27'C from +15OC to - 12'C even the more waxy Sumatran Light crude oil can be successfully treated.The additive retains its activity during storage and handling of the oil. It is destroyed at the refinery during distillation, and is not known to have any adverse side effects, neither in crude oil production nor in processing.At oil fields, paraffin deposits are often found in tubing and flow lines. A laboratory method using a capillary tube has been developed with which the formation of representative wax deposits and the influence of SHELLSWIM treatment there on can be studied.In extensive field trials in West-Africa, SHELLSWIM - 5 X and SHELLSWIM - 11 T SHELLSWIM additives proved to reduce effectively wax deposition, leading to a considerably smaller loss in production due to waxclogged lines.SHELLSWIM additives also improve the lowtemperature fluidity of the oil. It is for this property that the product will be used in the Sabah pipeline system which is coming on stream soon.Pumping of waxy crude oils through longdistance submarine and land pipe-lines involves the serious risk, that during an emergency shutdown and concomitant cooling of the oil the wax causes gelling of the crude oil, so that restarting the pipeline is impossible. Additive treatment can reduce the risk of pipeline blockage and extend the shutdown period permitted.A striking example is found in the waxy Bombay High crude oil, which is transported through 200 km of submarine pipeline. On the basis of experiments with the Shellmodel pipeline rig, SHELLSWIM-SX was selected by the Indian operator for continuous application to obtain safe transport of the crude oil. The additive proved its value when after a nineday emergency shutdown the pipeline was easily restarted.